When you look inward and realize you have an insecurity about something, it's often important to ask WHY.
It sounds so damn obvious, but tons of people just sit there and think they're stucking thinking things like "I don't feel I am good enough for others" etc.
I think I read something about this before called The Three Whys. Every time you ask why, you go in deeper and try and figure it out.
"I am upset this person hasn't gotten back to me"
"Why?"
"Well I know they're busy but what if they suddenly don't want to talk to me anymore."
"Why?"
"Why does that bother me? Because I've been programmed by others to think that they run because I'm not good enough."
Anyways, this is just my two cents when you're feeling down.